The oral cancer chemopreventive efficacy of lupeol, a bioactive triterpene, was assessed by monitoring the tumor incidence and using the status of phase I and II xenobiotic metabolizing enzymes, lipid peroxidation and antioxidants as biochemical end points during 7,12-dimethylbenz(a)anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Oral tumors were developed in the buccal pouch of golden Syrian hamsters by painting with 0.5 % DMBA three times a week for 14 weeks. Well differentiated oral squamous cell carcinoma with marked abnormalities in the status of biochemical markers were noticed in hamsters treated with DMBA alone. Oral administration of lupeol at a dose of 50 mg/kg bw completely inhibited the formation of oral tumors and restored the status of biochemical markers during DMBA induced oral carcinogenesis. The present study thus demonstrates the chemopreventive potential of lupeol in DMBA induced oral carcinogenesis. The chemopreventive potential of lupeol is probably due to its antioxidant or free radical scavenging property and modulating effect on phase I and II xenobiotic metabolizing enzymes in favour of the excretion of carcinogenic metabolites during DMBA induced hamster buccal pouch carcinogenesis.